One pass rolling mill plug and rolling plug mill

ABSTRACT

A ROLLING MILL PLUG FOR USE IN A SEAMLESS ROLLING PLUG MILL TO REDUCE AND ELONGATE THE PIERCED SHELL BEING FORMED INTO SEAMLESS PIPE AND CONSISTING OF A CYLINDRICAL BODY HAVING A PLURALITY OF SECTIONS OF DIFFERENT DIAMETERS SOME OF WHICH SECTIONS ARE OF UNIFORM DIAMETER AND SOME OF WHICH ARE FRUSTA-CONICAL.

Oct. 5, 1971 A. E. DELANS 3,610,012

ONE PASS ROLLING MILL PLUG AND ROLLING PLUG MILL Filed June 10, 1969 INVENTOR.

s FIG-5 ANDREW E. DELANS ATTORNEZ United States Patent 3,610,012 ONE PASS ROLLING MILL PLUG AND ROLLING PLUG MILL Andrew E. Delans, 7859 South Ave., Youngstown, Ohio 44512 Filed June 10, 1969, Ser. No. 831,885 Int. Cl. B21b 17/10 US. Cl. 72-209 3 Claims ABSTRACT OF THE DISCLOSURE A rolling mill plug for use in a seamless rolling plug mill to reduce and elongate the pierced shell being formed into seamless pipe and consisting of a cylindrical body having a plurality of sections of different diameters some of which sections are of uniform diameter and some of which are frusta-conical.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to rolling mill plugs as used in seamless mills for the production of seamless pipe from pierced shells.

(2) Description of the prior art Prior art rolling mill plugs have generally comprised modifications of an elongated plug shape, the forward portions of which are arcuate leading from the largest diameter of the plug to the smallest diameter thereof so that the pierced shell being passed thereover by the rolling mill rolls engages the arcuate curving surfaces of the plug to effect elongation and reduction of the wall thickness. Prior art rolling mill plugs have always required two passes of the pierced shell thereover in order to sufiiciently reduce the wall thickness and sufiiciently elongate the shell to form the desirable seamless pipe.

This invention eliminates the second pass at the configuration of the rolling mill plug disclosed herein results in a uniform reduced wall thickness and a desirable elongation of the shell to form the desired seamless pipe.

SUMMARY OF THE INVENTION A rolling mill plug of novel configuration incorporating adjacent cylindrical sections some of which are of uniform diameter and some of which are frusta-conical and wherein the taper of each of the frusta-conical sections is different from the other. The rolling mill plug incorporates metal working sections and heat sections adjacent thereto and is located between the rolls of the rolling plug mill to present the metal working sections between the areas of the largest diameter of the rolling mill rolls whereby a single pass of a pierced shell over the plug through the rolling plug mill will reduce the wall thickness uniformly and desirably elongate the shell to form the desired seamless pipe.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross-section through a portion of a rolling plug mill with parts thereof in cross section and parts broken away illustrating the rolling mill plug and a pierced shell in position therebetween.

FIG. 2 is an end elevation on line 22 of FIG. 1.

FIG. 3 is an enlarged cross-sectional elevation of portions of the rolling plug mill and the pierced shell therein and illustrating the novel configuration of the rolling mill plug.

FIG. 4 is a vertical cross-section on line 4-4 of FIG. 3.

FIG. 5 is a vertical cross-section on line 55 of FIG. 3.

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DESCRIPTION OF THE PREFERRED EMBODIMENT In FIGS. 1, 2 and 3 of the drawings a seamless rolling plug mill such as used for forming seamless pipe from pierced shells is illustrated and wherein the rolls are indicated at 10 and 11 with the oppositely disposed concave peripheral surfaces thereof being indicated by the numerals 12 and 13. The concave surfaces 12 and 13 conform with the exterior circular shape of a piece of seamless pipe which is circular in cross-section.

In FIGS. 1 and 3 a pierced shell S is shown entering the rolling plug mill rolls 10 and 11 from the left and moving toward the right and passing over the one pass rolling mill plug 14 which is held in position between the rolls 10 and 11 by a plug bar 15. The rolling mill plug 14 has an axial opening longitudinally thereof through which a plug pin 16 extends. The plug pin 16 is mounted in a socket in the end of the plug bar 15. The one pass rolling mill plug has a novel configuration which includes a plurality of frusta-conical portions 17, 18 and 19 respectively which are spaced longitudinally with respect to one another by cylindrical portions 20, 21 and 22 which are of different diameters and lengths.

It will be observed by referring to FIG. 3 of the drawings, that the frusta-conical portion 17 has a conical surface formed on an angle to the horizontal plug pin which is relatively greater than the comparable angle of the conical section 18 and that the angle of the frusta-conical section 18 is relatively greater than that of the section 19.

It will further be observed that the length of the section 17 is greater than that of the frusta-conical section 18 while the length of the frusta-conical section 19 is greater than that of the section 17. The metal working of the pierced shell 5 is performed by the trailing edge of the frusta-conical section 18, the cylindrical section 21 and the total surface of the frusta-conical section 19.

By referring to FIGS. 1 and 3 of the drawings, it will be observed that these metal working portions of the rolling mill plug are disposed in the area of the vertical axis of the rolls 10 and 11 which thereby hold the exterior diameter of the pierced shell S in desirable configuration and cause the metal working being performed by the rolling mill plug 14 to elongate the pierced shell as the same passes therebetween.

The degree of reduction is clearly illustrated in both FIGS. 1 and 3 of the drawings and is further illustrated in the cross sections comprising FIGS. 4 and 5 of the drawings.

By referring to FIG. 4 of the drawings, it will be observed that the pierced shell S has a Wall thickness substantially the same as that being introduced into the rolling plug mill, and by referring to FIG. 5 of the drawings, it will be seen that the wall thickness of the pierced shell S has been reduced to that desired in the finished seamless pipe. The degree of elongation which occurs in this operation is not illustrated but will be familiar to those skilled in the art. For example, a twenty-six foot pierced shell is generally elongated to forty-eight feet with the attendant reduction of wall thickness.

Those skilled in the art will observe that the temperature of the pierced shell S as it enters the rolling plug mill is generally in the vicinity of 1925 F. and that the metal working resulting in the reduction of the wall thickness and the elongation of the shell into the seamless pipe takes place at this desirable temperature. In comparison the prior art rolling plug mill received the pierced shell at the same temperature 1925 F. on its first pass and by the time the shell had been run on its second pass, the temperature was generally reduced to less than l800 and those skilled in the art will observe that the second pass at the lower temperature as heretofore customary resulted in double the wear on the rolling mill plug and the rolls and that the Wear factor increased because of the reduced temperature. It will thus be apparent to those skilled in the art that the present invention results in an improved seamless pipe as the metal is worked out its optimum temperature and the tools are subjected to a minimum of wear in the single pass required. In a typical example, the trailing edge of the frusta-conical section 18 and the cylindrical portion 21 result in a reduction of .062 of an inch in the wall thickness of the pierced shell S with the balance and obviously major portion of the reduction occurring on the frusta-conical portion 19 of the rolling mill plug.

It will thus be seen that the working of the metal of the pierced shell 13 occurs primarily on the three intermediate portions 18, 21 and 19 of the rolling mill plug 14. The adjacent portions 20 and 22 both of which are cylindrical are primarily provided to act as heat sinks to the metal Working portions 18, 21 and 19 and are essential to the operation thereof. Their configuration is of equal importance as the diameter of the cylindrical portion 20 is less than that of the pierced shell S and thereby is not engaged with the same and does not absorb heat therefrom and it is therefore capable of absorbing heat more readily from the adjacent working portions 18 and 21. The cylindrical portion 22 is of the same diameter as the reduced inner wall of the pierced shell S and engages the same as it leaves the largest diameter of the frusta-conical portion 19. The location and shape of the portion 22 insure the retention of the inner wall surface in the desired configuration and as aforesaid, act primarily as a heat sink with respect to the working portions 21 and 19 of the plug.

It will be observed further that each of the portions 20, 21 and 22 are of different lengths as occasioned by their specific functions as aforesaid. The leading frustaconical portion 1'7 and the following cylindrical portion ture in a single pass with a resultant reduced distortion of the exterior surface of the pierced shell.

It will be observed by those skilled in the art that rolling mill plugs heretofore used performed the metal Working on that portion of the pierced shell which was entering the rolls, for example, to the left of the axial center line of the rolls as seen in FIG. 1 of the drawings, while the device of the invention is so shaped and positioned that it works the metal both to the left and the right of the axial center line of the rolls which are engaging, the exterior ofthe pierced shell. The major part of the working taking place in the down stream portion of the pierced shell beyond the vertical center line of the rolls. Another result of this action is the production of a less eccentric wall than that formed on a regular rolling mill plug.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention and having thus described my invention, what I claim is:

1. The combination of a rolling plug mill for forming seamless pipe from a pierced shell and a rolling mill plug for use therein, said mill including a pair of vertically spaced rolls on parallel axes and having oppositely disposed peripheral grooves therein for engaging said pierced shell, said rolling mill plug comprising an elongated cylindrical body member having several frusta-conical portions of different diameters and lengths and several cylindrical portions of different diameters and lengths spacing said frusta-conical portions, said rolling mill plug being positioned with the largest diameter frusta-conical portion thereof downstream of the vertical center line of said rolls.

2. The combination of claim 1 and wherein said largest diameter frusta conical portion is of a greater length than said other frusta-conical portions of said plug.

20 also function in stopping cobble which occurs due to irregularity in the inner surface of the pierced shell S and additionally, insure the proper alignment of the one pass rolling mill plug with the pierced shell S.

Those skilled in the art will observe that rolling plug mills producing seamless pipe generally form a pair of oppositely disposed ribs longitudinally of the pipe which occurs because of the spacing between the peripheral edges of the rolls and the fact that they do not completely contact the exterior diameter of the pierced shell. The present invention eliminates a majority of the ribs heretofore formed in the seamless rolling plug mills and that that is formed is easily removed by the reeler which engages the newly formed seamless pipe in an immediately following operation. It is believed that the absence of the heretofore believed necessary ribs on the exterior of the seamless pipe as formed on a conventional rolling plug mill with a conventional rolling mill plug is due to the novel configuration of the rolling mill plug and the fact that it is working the metal at its optimum tempera- 3. The combination of claim 1 and wherein one of said cylindrical portions is located on either side of said largest diameter frusta-conical portion so as to act as a heat sink with respect thereto.

References Cited UNITED STATES PATENTS 1,498,130 6/1924 Stiefel 72-97 1,837,161 12/1931 Herz 72-209 1,843,395 2/1932 Lauterbach 72-97 1,939,526 12/1933 Steinecke 72-97 2,176,155 10/1939 Stiefel 7297 2,778,253 1/1957 Brownstein 72209 3,296,848 1/1967 Murphy et al. 7297 X MILTON S. MEHR, Primary Examiner US. Cl. X.R. 72-97 

